A5048860722- Terahertz technology and applications
- Photonic and Optical Devices
- Advanced Optical Imaging Technologies
- Photonic Crystals and Applications
- Superconducting and THz Device Technology
- Digital Holography and Microscopy
- Photorefractive and Nonlinear Optics
- Metamaterials and Metasurfaces Applications
- Optical Coatings and Gratings
- Microwave Engineering and Waveguides
- Advanced optical system design
- Spectroscopy and Laser Applications
- Optical Polarization and Ellipsometry
- Liquid Crystal Research Advancements
- Advanced Antenna and Metasurface Technologies
- Optical measurement and interference techniques
- Millimeter-Wave Propagation and Modeling
- Plasmonic and Surface Plasmon Research
- Orbital Angular Momentum in Optics
- Electromagnetic wave absorption materials
- Semiconductor Lasers and Optical Devices
- Advanced Photonic Communication Systems
- Photochromic and Fluorescence Chemistry
- Random lasers and scattering media
- Thermal Radiation and Cooling Technologies
Warsaw University of Technology
2016-2025
Abstract Over the last 20 years, thin and lightweight optical elements have become very desirable, especially for terahertz (THz) range. Reduction of volume alongside an increase in their effective efficiency has begun a new direction research leading to many practical applications. On top that, diffractive can not only focus incident beam, but also shape incoming wavefront into desirable distribution or redirect energy. Starting from theoretical calculations Fourier optics, been transformed...
A method of color image projection is experimentally validated. It assumes a simultaneous illumination spatial light modulator (SLM) with three laser beams converging in common point on screen. The are masked amplitude filters so that each one illuminates third the area SLM. Fourier hologram chosen component an input calculated, and its phase pattern addressed corresponding part SLM area. full-color flat formed screen as result mixing. Additional techniques optimization applied:...
Passive terahertz (THz) setups require optical elements with large diameters for optimal harvesting of weak signals. High f-number implies sophisticated aspheric designs to ensure resolution and good energetic efficiency. Trial error testing such optics is expensive numerical modeling time consuming; hence, we propose extremely cheap diffractive lenses THz made regular paper. They are easy manufacture even diameters, the function can be easily customized, which used initial experimental...
THz beam shaping via a single diffractive optical element is used to convert divergent into focal line segment perpendicular the axis. The novel structure was designed for narrowband applications as kinoform and we successfully applied it in active, high-speed, linear scanners. theoretical approach experimental results are presented.
The majority of industry using high-speed communication systems is shifting towards higher frequencies, namely the terahertz range, to meet demands more effective data transfer. Due rising number devices working in shielding electromagnetic interference (EMI) required, and thus need for novel materials reduce pollution. Here, we show a study on optical electrical properties series ethylene co-butyl acrylate/carbon black (EBA/CB) composites with various CB loading. We investigate...
Surface relief grating formation in photo-responsive azo polymers under irradiation is a long-ago-found phenomenon, but all the factors governing its efficiency are still not fully recognized. Here, we report on enormous impact of polymer thickness possibility fabrication extremely high-amplitude surface deformations. We performed prolonged holographic recordings layers same azobenzene poly(ether imide), which had substantially different optical transmittances at recording wavelength and...
Terahertz radiation patterns can be registered using various detectors; however, in most cases, the scanning resolution is limited. Thus, we propose an alternative method for detailed of terahertz light field distributions after passing simple and complex structures. Our relies on a dielectric waveguide to achieve better sampling resolution. The optical properties many materials were analyzed time-domain spectroscopy. A cyclic olefin copolymer (COC) was chosen as one transparent. This study...
An iterative phase retrieval method for a lensless color holographic display using single light modulator is experimentally validated. The technique involves calculation of three-plane synthetic hologram which displayed on SLM simultaneously lit with three laser beams providing an RGB illumination. Static and animated two-dimensional flicker-free full images are reconstructed at fixed position captured high resolution CMOS sensor. image finesse, fidelity, contrast ratio influence speckles...
Multifunctional materials are the future of modern electronics. The reduction weight and no interfacial mismatches perfectly fit requirements those industry sectors which require miniaturization, low weight, high functionality, like aerospace or wearable Here, we show multifunctional thermoplastic polymer composites based on acrylonitrile–butadiene–styrene (ABS) with graphene nanoplatelet (GNP) inclusions at different loadings GNPs, from pure up to 10 wt %. multifunctionality is expressed...
Modern passive THz setups require effective optical elements with a large numerical aperture. Here we propose new type of the element for applications, which is broadband double-sided Fresnel-like lens an optimized thickness. The optimization performed to obtain very low attenuation, material cost, and small weight in media. It also provides achromatic properties assumed wavelength range. experimental evaluation proposed diffractive by means time-domain spectroscopy presented discussed.
The recent fast development of terahertz technology finds applications in many technological aspects used security, medicine, biology, telecommunication, astronomy, and others. Each them requires individual optical components made well-performing materials adapted to the particular application. This work examines properties different polymer 3D printing techniques examined verified by time-domain spectroscopy. Moreover, composite significantly influence on base mechanical performance.
A diffractive optical element for off-axis focusing of terahertz radiation is presented. It was designed in a nonparaxial regime and manufactured metal slab by laser cutting curved stripes. The function the structure includes deflecting illuminating beam chosen frequency particular place. Therefore, acts as both spatial spectral filter; hence it especially suitable separating signal from broadband thermal load passive detection devices. experimental evaluation proposed lens means time-domain...
An improved efficient projection of holographic images is presented. It uses two phase spatial light modulators (SLMs) with iteratively optimized Fresnel holograms displayed simultaneously--each for one modulator. The distribution on the second modulator taking into account coming from first one. A pixelated structure and fluctuations liquid-crystal molecules cause a zero-order peak that was separated in experiment. Use SLMs gives clear containing almost no speckles images. Thanks to...
An improved efficient projection of color images is presented. It uses a phase spatial light modulator with three iteratively optimized Fourier holograms displayed simultaneously--each for one primary color. This division instead time provides stable images. A pixelated structure the and fluctuations liquid crystal molecules cause zeroth-order peak, eliminated by additional wavelength-dependent factors shifting it before image plane, where blocked matched filter. Speckles are suppressed...
We discuss thin optical structures that allow chromatic aberrations to be avoided in the THz domain. The paper contains theoretical considerations, computer modeling and experimental evaluation of high order kinoform diffractive elements range. According obtained results application kinoforms enables broadband operation
Terahertz (THz) imaging can serve as a versatile instrument to disclose contents of various packages or discriminate its constituents. Particular attention deserves case when packaged objects display low absorption in THz frequencies inducing thus immense obstacles direct image recording due poor signal-to-noise ratio and small contrast. To tackle these problems extend an assortment application two spatial filtering methods – phase contrast dark field were demonstrated both experimentally...
Recently, one of the most commonly discussed applications terahertz radiation is wireless telecommunication. It believed that future 6G systems will utilize this frequency range. Although exact technology telecommunication not yet known, it certain methods for increasing their bandwidth should be investigated in advance. In paper, we present diffractive optical elements division multiplexing waves. The structures have been designed as a combination binary phase grating and converging lens....
Fast and intensive development of terahertz (THz) technology requires designing dedicated optical elements. Here, we generated complicated THz field distribution thanks to simple binary diffractive elements (DOEs) made from paper. The paper fabricated structures are lightweight, inexpensive, feasible for fast-prototyping purposes they have high transparency in the range. Structures were designed simulated nonparaxial approach which suppresses influence geometrical aberrations enables large...
This paper presents a convolutional neural network approach for the design and optimization of single-input-multiple-output (SIMO) structures sub-terahertz spectral range (140 GHz). Two SIMO with two output channels have been designed using proposed an iterative algorithm as reference. Both manufactured by means fused deposition modeling 3D printing technique verified experimentally. A new method phase maps has developed applied to manufacture unintuitive optimized networks.
Abstract The rising demand for faster and more efficient electronic devices forces electronics industry to shift toward terahertz frequencies. Therefore there is a growing need efficient, lightweight, easy produce absorbing materials in the range electromagnetic interference (EMI) shielding related applications. This study presents on basic optical properties of two types polymer‐based composites loaded with two‐dimensional structures—graphene MXene phases (Ti 2 C). In said range, total EMI...
Many modern and future systems, based on the wireless communication at THz frequencies, could benefit from multichannel transmission. One of possible approaches is to (de)multiplex several separate signals a single transmission channel using dedicated diffractive optical elements. Proper selection receivers for such systems crucial strongly depends not only frequencies used but also geometry setup. In this article, we present complex analysis applicability various detectors characterization...